Change the price of an item in a basket by user field, Woocommerce

Question

I currently have a problem when I need to add an option to the cart with a checkbox (for each item in the cart) that will change the price of the product using one of the custom attribute.

This is an illustration (I already created a custom field, I just need the function of updating the price when I click the "Update Cart" button)

Code to display a check box for each item (/woocommerce/templates/cart/cart.php):

<td class="product-url">
    <?php
        $html = sprintf( '<div class="lorem"><input type="checkbox" name="cart[%s][lorem]" value="%s" size="4"  class="input-text url text" /> Lorem price</div>', $cart_item_key, esc_attr( $values['url'] ) );
        echo $html;
    ?> 
</td>

Answer 1

Here I assume that lorem priceis stored in a custom meta field associated with meta_keyyour_custom_meta_field

function.php file

add_action( 'woocommerce_before_calculate_totals', 'my_custom_calculate_totals' );
function my_custom_calculate_totals( $cart ) {
    if ( ! empty( $cart->cart_contents ) ) {
        $lorem_price = array();
        if ( ! empty( $_REQUEST['cart'] ) ) {      // check if any of the checkboxes is checked
            WC()->session->set( 'my_lorem_price', $_REQUEST['cart'] );      // set all checkboxes information in session
            $lorem_price = $_REQUEST['cart'];
        }
        if ( empty( $lorem_price ) ) {
            $lorem_price = WC()->session->get( 'my_lorem_price' );      // fetch all checkboxes information from session
        }
        if ( empty( $lorem_price ) ) {
            return;     // don't do anything if any of the checkboxes is not checked
        }
        foreach ( $cart->cart_contents as $cart_item_key => $cart_item ) {
            if ( isset( $lorem_price[ $cart_item_key ]['lorem'] ) ) {
                // Use following line if lorem price is set at variation level
                $id = ( ! empty( $cart_item['variation_id'] ) && $cart_item['variation_id'] > 0 ) ? $cart_item['variation_id'] : $cart_item['product_id'];
                // Use following line if lorem price is set at product level
                // $id = $cart_item['product_id'];
                $new_price = get_post_meta( $id, 'your_custom_meta_field', true );      // fetch price from custom field
                $cart_item['data']->price = $new_price;
            }
        }
    }
}